Back in the older days SR5 actually meant a Sport Package. These days SR5 denotes "base model."
In the 4th gens (2003-2009) & 5th Gens (2010+) SR5 translates to "Base Model." With the 4th Gens there was a "Sport" Trim level that meant you got larger brakes (now standard on 5th gen models and we optional on 4th gen Limited models), color matched pieces, sport hood, ect. V6 & V8 were engine option across all Trims (I own a V8 Sport myself, but V6 Sport is also available as are V6/V8 SR5 & Limited.)
I have never seen a Winebago topped 4Runner, unless you are referring to an old 1st gen that had removable tops? The 4Runner "Highlander Edition" was a trim level for the 3rd Gens prior to the release of the Highlander model we now see everyday and is not related to that model in any way besides coincidental naming (I don't know where you got Accord based from as that is Honda. The Highlander is its own platform, distantly based on a Camry if anything.)
As far as I am aware an Inline-6 Was never offered for the 4Runners, it has only be 4cyl, 6cyl, and 8cyl gasoline engines and 4cy diesels.
Overseas the 4Runner was marketed as the "Hilux Surf" despite the fact that when the 1st Gen Tacoma & 3rd Gen 4Runner were developed they were designed on a different frame while the Hliux remained on the same frame it carries today. So over seas a 2004 Hilux Surf is almost a complete re-badge of a 4th Gen 4Runner.
I would recommend you Google the history of the 4Runner to get a better idea of the vehicle as there is a lot of information to cover in the 30+ years these vehicles have been around let alone how they tie into the Hilux, FJ Cruiser, Tacoma, GX470/GX460, Prado 120/150, ect.
